Calibration of the biotrainer pro activity monitor in children

Welk, Gregory J., Eisenmann, Joey C., Schaben, Jodee, Trost, Stewart G. and Dale, Darren (2007) Calibration of the biotrainer pro activity monitor in children. Pediatric Exercise Science, 19 2: 145-158.

Author Welk, Gregory J.
Eisenmann, Joey C.
Schaben, Jodee
Trost, Stewart G.
Dale, Darren
Title Calibration of the biotrainer pro activity monitor in children
Journal name Pediatric Exercise Science   Check publisher's open access policy
ISSN 0899-8493
Publication date 2007-05-01
Sub-type Article (original research)
Volume 19
Issue 2
Start page 145
End page 158
Total pages 14
Place of publication Champaign, IL, United States
Publisher Human Kinetics
Language eng
Subject 1106 Human Movement and Sports Science
Abstract The unique physical and movement characteristics of children necessitate the development of accelerometer equations and cut points that are population specific. The purpose of this study is to develop an ecologically valid cut point for the Biotrainer Pro monitor that reflects a threshold for moderate-intensity physical activity in elementary school children. A sample of 30 children (ages 8–12) wore a Biotrainer monitor while completing a series of 7 movement tasks (calibration phase) and while participating in an organized group activity (cross-validation phase). Videotapes from each session were processed using a computerized direct-observation technique to provide a criterion measure of physical activity. Analyses involved the use of mixed-model regression and receiver operator characteristic (ROC) curves. The results indicated that a cut point of 4 counts/min provides the optimal balance between the related needs for sensitivity (accurately detecting activity) and specificity (limiting misclassification of activity as inactivity). Results with the cross-validation data demonstrated that this value yielded the best overall kappa (.58) and a high classification agreement (84%) for activity determination. The specificity of 93% demonstrates that the proposed cut point can accurately detect activity; however, the lower sensitivity value of 61% suggests that some minutes of activity might be incorrectly classified as inactivity. The cut point of 4 counts/min provides an ecologically valid cut point to capture physical activity in children using the Biotrainer Pro activity monitor.
Keyword Accelerometer
Biological monitoring
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status Non-UQ

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Created: Tue, 10 Mar 2009, 23:58:57 EST by Maryanne Watson on behalf of School of Human Movement and Nutrition Sciences